The Creamy Ingredients That Have No Place In Mashed Potato Casserole
The trouble with mashed potatoes is that you really need to make them and serve them right away. They're just never the same if you reheat them and try to get that perfect fluffy texture. When cooking a big dinner, some people are absolutely masterful at timing all of their dishes so that fresh mashed potatoes hit the table at the same time as the entree and salad. But others might struggle with this, or prefer to make things in advance that can be heated and served when it's time to eat so that your dinner party is a more relaxed occasion. A perfect middle-ground option for potato lovers is a mashed potato casserole.
The idea is to make mashed potatoes with whatever mix-ins you like: Chives, bacon, shredded cheese, or scallions, and then layer them in a casserole dish before topping them with breadcrumbs (optional) and baking. While you do want to add some creamy ingredients to the casserole such as sour cream, or cream cheese there are a few creamy options that just don't work well with this dish and should therefore never be used.
Although bechamel is the pinnacle ingredient in a mac and cheese casserole, you don't want it anywhere near a mashed potato casserole. Similarly, Greek yogurt has no place in this dish and neither does mascarpone cheese. If it seems peculiar that you could add cream cheese to a mashed potato casserole but not mascarpone, let's get into why.
Some creamy add-ins just don't work
Some people swear by adding a dollop of full-fat Greek yogurt to a baked potato or to mashed potatoes, but you don't want to use this ingredient in a mashed potato casserole. Although fresh Greek yogurt might add a nice, cool, tangy flavor to a baked potato, you certainly can't cook it and expect its flavor and texture to remain the same. Mashed potato casserole is baked before serving and baking Greek yogurt messes with the flavor and moisture. And while cream cheese and sour cream can be heated in an oven and still add moisture and flavor, Greek yogurt will get dry and the tangy flavor will give off the taste and aroma of sour milk.
A bechamel sauce is another creamy ingredient often associated with potatoes. But just because it's great in potatoes au gratin doesn't mean it will work in a casserole. In that case, the mixture of the mashed potatoes and sauce creates a flour-like taste that confuses the palate.
Mascarpone is sometimes thought of as Italian cream cheese, but it's way richer. While cream cheese contains 33% milk fat, mascarpone contains a whopping 60% to 75%. Adding mascarpone to a mashed potato casserole will make it far too rich. So although you definitely want to add creamy ingredients to your mashed potato casserole, stick with sour cream or cream cheese for the best results.